Method of making hollow articles



Nov. 28, 1939. G. H. PHELPS El AL 2,181,201

METHOD OF MAKING HOLLOW ARTICLES Filed Aug. 25, 1936 2 Sheets-Sheet l INVENTORS GEo/PGEH PHEL PS BY IZE- WPrS Z261. Ms

METHOD OF MAKING HOLLOW ARTICLES Filed Aug. 25, 1936 v 2 Sheets-Sheet 2 24*L 27 24 25' 27 21 fiy 1 I y .fi'A/RVAS 1964. M S.

ATTORNEYS Patented Nov. 28, 1939 UNITED STATES PATENT OFFICE METHOD OF MAKING HOLLOW ARTICLES George H. Phelps, Floral Park, and Henry S.

Holmes, Brooklyn, N. Y., assignors to Metropolitan Engineering Company, Brooklyn, N. Y., a corporation of New York Application August 25, 1936, Serial No. 97,739

8 Claims.

The invention aims to provide an improved method of making hollow articles, such as an agile housing or a torque rod of an automobile and similar aromas}; be designated generally as being of mechanical tubing, by which they can be made better and more cheaply. The invention also provides improved blanks for drawing or fabrication into hollow articles.

The accompanying drawings illustrate embodiments of the invention.

Figs. 1, 2, 3 and 4 are, respectively, a side elevation, end elevation, section on line 3-3, and plan view of a rear axle housing.

Fig. 5 is a plan of a blank therefor.

Figs. 6, 7 and 8 are, respectively, a side elevation, section on the line l-l, and plan view of a torque rod.

Fig. 9 is a plan view of a blank therefor.

Figs. 10, 11 and 12 are, respectively, a side elevation, section on the line ll-H, and plan of another design of torque rod.

Fig. 13 is a plan of a blank therefor.

In making formed sheet metal parts the common procedure is to use a metal soft and ductile enough to withstand the draw at that point at which the metal is most severely strained in forming, and to use this metal in a thickness sufficient to give the required strength at the point of greatest stress in use. In a great many cases this results in a finished part which is much heavier than is desired and, in fact, heavier than would be necessary if metal of greater unit strength could be drawn into the required shape.

The rear axle and torque arms described in this application are parts of an automobile. They are of necessity part of the unsprung weight of the car. It is desirable to keep this unsprung weight as light as possible. This reduction in weight may be gained by the use of alloy steel of high tensile strength. Hitherto, however, it has been found impracticable to form such alloy steel into the desired shape. This inventior allows us to overcome this difiiculty.

It often happens that one part of a starr ping is quite dificult to draw or form and consequently must be of very ductile metal, while another portion of the stamping may be of such a shape as to form very easily even from comparatively rigid and strong material. In almost all such cases that part of the stamping which is irregular or intricate in shape and, therefore, dimcult to draw is not subjected to high unit stresses in use, for severe drawing hardens and stiffens the metal at this point and the shape formed is usu ally one of high moment of inertia and great inherent strength and stifiness. However, other parts of the stamping, where the shape is simple and the draw not severe, are often highly stressed in use.

In Murray Reissue Patent No. 16,691 August 5 2, 1927, and Patent No. 1,887,494 November 15, 1932, there is disclosed a method of making rear axle housings and the like by the use of composite blanks in a way to diminish scrap losses. Those inventions have reduced the cost of the stampings for such articles. By the present invention still further advantages are gained in connection with the use of composite blanks. The sections for the blanks are so selected and are made of metal of such different properties and, sometimes, thicknesses as to be most nearly ideal in production and in finished properties for the particular parts of the article which they ultimately constitute. In different sections of the composite blank we use different metals, each of suflicient ductility to withstand the draw at that particular point but of the maximum tensile and fiexural strength consistent with such ductility, and of sufiicient thickness to result in the required total strength.

The invention makes it possible to save weight by using sections of the same thickness, but of different compositions, or by varying both the composition and the thickness in different sections of a composite blank. With any given metal, saving of weight is a saving in cost besides the advantage of lightness in product. Generally, the metal for products of this sort would be steel, but there are many varieties of steel, in which term we include steel alloys, varying greatly in their physical properties. The results desired will generally be obtainable by the use of different steels at different points.

The designer is enabled by this invention to choose for each part of the blank the most economical material in the most economical thickness. Furthermore, if light weight of the finished article is in itself of value, he can use thin, light, high strength materials in those parts of the blank in which drawing is not severe, and a heavier gauge of deep drawing or other more ductile material only in those sections where the severe draw requires it. According to the previous practice he would be required to use this heavier gauge of drawing stock throughout the blank.

Referring now to the particular embodiments of the invention illustrated, the rear axle housing of Fig. 1 is, for the purpose of this invention, made up of a central portion I l and end portions I 2. On the outer ends of the latter are heavy flanged end pieces l3, which constitute no part of 55 this invention, and which may be of various available designs. The center section II includes the annular portion I 4 of the gear casing and two tubular extensions 15 of tapering form carrying the inner portions of the drive shafts. The sections i 2 are straight tubular pieces of uniform diameter from end to end. They carry blocks or plates IE to take the bearing of the springs on the axle housing. The center section II is blanked separately from the end sections l2 because these require steel of different properties. The center portion requires a deep drawing steel. If the same steel were used throughout the length of the housing, the end sections l2 would be weaker than the center portion. But these end sections, where the springs are attached, require the greatest strength.

We, therefore, make a blank l1, Fig. 5, for the center section II of deep drawing steel, such for example as low metalloid steel containing say, carbon 0.10% and under, manganese 0.045% and under, phosphorus and sulphur as low as possi ble, and blanks i8 for the end sections are of a high tensile alloy steel such, for example, as high carbon, that is, above 0.3%, or steel alloys of chrome, chrome vanadium, manganese, etc. Flat stampings of these metals are welded together at their ends along the lines IS. The blank is then drawn or bent up around its longitudinal axis to segmental shape. The shape of the central section is indicated in Fig. 3. The shape of the end sections is substantially a semi-circle. Two such segments are then welded together along the line 20, Fig. 1, to make the completed housing as we use the term herein. End pieces l3 are afterwards applied, as by welding, along the lines 2|. The usual trimming and finishing operations are assumed.

The welding operations are not necessarily performed in the sequence stated, though that is the preferred method. The drawing and bending operation may be simplified, however, by performing them separately on the sections shown in Fig. 5, and then welding the ends of the resulting segments together. Or the sections may be separately drawn and bent to segmental shape and welded together along their longitudinal edges to form separately the section I l and the two end sections I2 of Fig. 1; these tubular pieces being then welded together end to end.

The shapes of torque arms shown in Figs. 6 to 13, are the subject of a separate patent of Soehner and Holmes, 2,105,132, January 11, 1938. The one illustrated in Fig. 6 comprises a hollow spherical inner end 22 and an intermediate tubular member 23 flaring in height but of uniform width. At its large end it merges into a hollow portion 24 of the same uniform width and of varying height, through which is a transverse opening 25 formed by bent in flanges 26 (Fig. 7). On the outer end of this member 24 there is a cup-shaped reinforced end plate 21. The parts (omitting the end piece 21) are made of a composite blank shown in Fig. 9 which is drawn up at the outer edges and around the opening 28; two of these segmental members being then welded along the longitudinal line 29, Fig. 8. The blank of Fig. 9 is made of two pieces welded together along the line 30. The piece 3|, which is to form the enlarged apertured portion of the bar, is made of a more ductile, deep drawing steel than the portion 32 which forms the spherical end 22 and the main tubular portion 23. In this case the part 24 also demands the greatest strength in use. The corresponding section 3| of the blank is,

therefore, made of a heavier steel. The part 32 may be made comparatively light by using a high tensile alloy steel. The welding operations in this case may be varied the same as in making the housing of Fig. 1.

The torque rod of Fig. 10 has a body portion 32, varying slightly in depth, and of uniform Width and of a much simpler form than that of Fig. 6. The inner end portion 33, however, is more complicated in shape, being a ring or hollow annulus with a transverse opening 34 flared to permit sidewise movement in addition to vertical movement about a pivot. A heavy outer end piece 35 is welded to the body.

A composite blank for the body portion and the inner end is illustrated in Fig. 13, comprising a portion 36 for the body and another portion 31 for the end piece welded to each other at 31a. These are drawn and bent up to form segments which are welded together along the longitudinal line 38, Fig. 10. The portion 31 of the blank for the apertured inner end 33 of the rod is subjected to a deeper and more complicated drawing operation and is made of a deep drawing steel. The portion 36 for the body section 38 of the rod requires strength and is made of high tensile alloy steel.

The welding operations in this case, as well as in those previously described, may be performed in different orders or sequences. Also, in any case, the halves or segments may be first formed by bending and drawing to a partial extent, then welded and thereafter re-formed to the perfect shape desired, either with or without re-heating after welding.

The composite blanks may be handled as complete articles of commerce made either in fiat or segmental shape for the full length of the finished stamping and sold to customers who press and draw them and weld them together with such further incidental operations as may be necessary.

Various other modifications may be made by those skilled in the art without departing from the invention as defined in the following claims.

What we claim is l. The method of making hollow articles of the character described which comprises stamping out pieces of sheet metal corresponding to certain parts of the article, those for one part having different ductility and strength from those for other parts, welding said pieces together to produce fiat blanks, bending said flat blanks into segmental blanks, and welding said segmental blanks together to form the hollow article.

2. The method of making hollow articles of the character described which comprises forming segmental blanks of sheet metal with a plurality of pieces in the length of each blank, said pieces differing from each other in ductility and strength, and welding said blanks together to form the hollow article.

3. The method of making hollow articles of the character described with different portions of its length composed of metal of different properties, which comprises drawing segments of sheet metal of certain determined properties and welding them together to form one portion, drawing segments of sheet metal of certain other determined properties, welding them together to form another portion, and welding such portions to each other 4. The method of making hollow articles of the character described, which comprises stampout pieces of sheet metal corresponding to certain selected parts of the article, those for one part having diflerent ductility and strength from those of other parts, and forming the articles from such pieces by a combination of drawing 5 and welding operations.

5. A composite blank for forming hollow sheet metal articles of the character described, consisting of a plurality of pieces welded together end to end, the pieces being of metal of difierent 1 properties, one or more having greater deep drawing property and another higher tensile strength.

6. A composite blank for forming hollow sheet metal articles of the character described, consisting of a plurality of pieces of steel welded together end to end, the pieces being of steel of different properties, one or more having greater deep drawing property and another higher tensile strength.

7, A composite blank for forming hollow sheet metal articles 01 the character described and comprising a continuous seamless sheet oi: metal having areas ofdifierent properties, one having greater deep drawing properties-and another having higher tensile strength.

8. A composite blank for forming hollow sheet metal articles of the character described and comprising a continuous seamless sheet of metal having areas of difierent properties, one vhaving great- 

